Tech Tent 17: Alibaba expansion

Alibaba, China's largest online retailer has taken a step closer to listing on the US stock market in what will be one of the largest share sales in history. What will this mean for its competitors?

Taxi drivers worldwide have been protesting about new apps that allow customers to book a driver and a car using a map on their smartphone. How is this technology disrupting the market and what will be the outcome?

Author and computer programmer Vikram Chandra talks "macho" geek culture.

Rory Cellan-Jones presents with studio guest Stuart Miles from Pocket Lint